I am going to put some music and movies on it tonight to give XBMC a proper testing.
And I am going to install Skyrim and Diablo 3 on it to give it a bit of a testrun. See how much gfx power the FX4100 paired with the HD6950 can handle. Do maybe a prima95 run to test temps and stability. If my temps have room I will also overclock the FX a bit.
Up untill now (just doing installaions and such) the GPU is about 30-35 degrees and the CPU is about 35-40 degrees. But the H70 on the CPU only has a PUSH fan due to room limitations while the GPU has PUSH-PULL. I wish I could have switched but there just isn't enough room in the case. In a regular case I could have done that. So I'll see what the temps will be doing.
This weekend I will be buying some maskingtape and double sided extra strong sticky tape to mod the top panel and fit the window.